(T1030-01-02) Enhancement of Permeation of an Anti-Glaucoma Medication Brinzolamide via OcuSurf™ Lipid Nanoparticles

Purpose: Ocular disorders in both developed and underdeveloped countries include high incidences of glaucoma, age-related macular degeneration, uveitis, corneal neovascularization, choroidal neovascularization, diabetic edema, diabetic retinopathy and geographic atrophy, etc. many of which affect vision with a high risk of blindness if left untreated. Since many of these disorders affect the aging population, the financial burden of clinician visits, treatment modalities, disease management and lifestyle changes as a result of blindness can amount to billions of dollars world-wide. Anterior eye disorders such as dry eye, blepharitis, corneal neovascularization, etc. are treated with steroidal anti-inflammatories and immunosuppressants. These medications are comprised of insoluble drug suspensions which are low in bioavailability. Posterior disorders are treated with intravitreal injections, increasing risk of retinal detachment, infections, macular holes and high incidences of “floaters”. An eye-drop approach that can rapidly penetrate the ocular tissues to reach posterior compartments of the eye (retina, choroid, etc.) is considered to be the holy grail, since this may eliminate injections. An eye-drop that permeates to posterior tissues has the potential to relieve the burden and risk of intravitreal injections. We have developed OcuSurf LNP, a liquid crystalline lipid nanoparticle eye-drop to address the clinician need as stated above. Brinzolamide, a carbonic anhydrase inhibitor is a hydrophobic anti-glaucoma drug approved and commercialized as a 1% eye-drop suspension (Azopt™, Alcon). The drug is formulated as a micro-suspension which results in sub-optimal absorption by ocular tissues and consequently, requires frequent dosing (3-4 times/day). A feeling of graininess is a frequent complaint by users. However, Brinzolamide has been reported to increase optic nerve blood flow, an effect that can enhance the therapeutic effect of the drug. We hypothesized that a more potent anti-glaucoma therapy using brinzolamide can be developed with the OcuSurf LNP delivery system.

Methods: OcuSurf-Brinzolamide: was prepared as a nano-dispersion using a proprietary process. Drug Content Analysis: of OcuSurf Brinzolamide was measured by a HPLC method, using a Shimadzu Prominence HPLC. Particle Size Distribution (PSD): Particle sizing was carried out using a laser diffraction method (Horiba 950V2). Corneal/ Scleral Permeability: Permeation was evaluated by mounting excised tissue sections of cornea and sclera (n=3 per tissue, per formulation) onto 5-mL Franz diffusion cells. The donor chambers were each filled with 100µL of formulation. The receptor solution was 5% w/w PEG-35-castor oil. Time points were taken every hour for five hours and assayed by LC/MS/MS. Bioanalysis: Analysis was performed by LC/MS/MS, Thermo Scientific TSQ Quantum Ultra Mass Spectrometer with HESI-I electrospray probe, paired with Shimadzu Nexera-i LC-2040C 3D Plus and using a Waters Sunfire C18, 100Å, 4.6 x 150 mm, 3.5 µm. Ocular Exams: Each animal underwent gross examination of the eye observing structures such as the cornea, conjunctiva, lids, etc., for obvious signs of issue. Scores were given on the SPOTS scoring system. Both eyes were examined at baseline and just prior to euthanasia. Endpoints included conjunctival hyperemia, iridial hyperemia, cornea (looking for haze or neovascularization), aqueous (to the best of the observer’ ability without dilation), chemosis, lid swelling, discharge, squinting, and pupillary light reflex (PLR). Euthanasia/Necropsy/Tissue Collection: Approximately 5 hours post the very first dose (1 hour post the 4-hour dose), each animal was sedated per Testing Facility SOPs. Each eye was collected and further dissected as follows: lens, aqueous humor, iris/ciliary body, vitreous, retina, RPE/choroid, optic nerve, and remaining scleral cup. Upon enucleation, the whole eye was rinsed in a minimal volume (2-5 mL) of phosphate buffered saline (PBS) to remove residual test article prior to full dissection. All samples were placed on dry ice and stored at -80^oC, until analysis.

Results: High permeation rates of the drug were observed in the OcuSurf-BZ cohort, in both in-vivo and in-vitro studies. In contrast, BZ permeation rates were many-fold lower in the Azopt cohorts. OcuSurf-BZ eye-drops were well tolerated in rabbit eye.
OcuSurf-BZ LNP were demonstrated to be stable, and largely non-settling over a 8 hour period.

Conclusion: Study demonstrates that it is possible to achieve significant levels of Brinzolamide in ocular tissues, using OcuSurf (at ½ the dose of Azopt). Continued modifications to the formulation compositions are underway to maximize drug exposure in tissues and to accomplish sustained levels (achieve once/day delivery).

Acknowledgements: All animal studies were performed at Pine Acres Rabbitry Farm, under approved IACUC protocol.

OcuSurf Lipid NanoParticles